Compressed air

Compressed air is used for a variety of purposes, in a variety of places, by a variety of people, and from observation, many people are not fully aware of the dangers associated with its use.

The majority of fatalities associated with the wrong uses of compressed air are attributed to sky-larking and horseplay; however, many people have been seriously injured and some killed by using the wrong method when carrying out legitimate work with compressed air.  

Air under pressure can be just as dangerous as high pressure steam, and when released suddenly can cause serious injury. It can maim, tear, or embed matter into the skin and bones of the human body. Air played around the face can blow out an eye, or if directed at the ear, it may puncture an ear drum and cause deafness. A person who has been painting or covered with dirt or soot can have poisonous particles blasted into the body where they immediately combine with the blood. Even air without impurities is dangerous when forced into the bloodstream through a cut or pores of the skin.  

Some people believe that air in the bloodstream will cause a joint or other affected part to swell up (accompanied by severe pain) and cause small blood vessels of the brain to burst. This is only partly true. People have died because their bowel ruptured as a result of pressure as low as four pounds per square inch (28 kPa). Many other injuries have occurred with pressures of 70 to 105 kPa.  

In some industries, horseplay with compressed air is a punishable offence. To point an air hose at a person is as serious an offence as to point a gun. It is worth remembering that clothing offers no more protection against compressed air than it does against a bullet.  

The use of compressed air to blow away dirt, chips, iron fillings, or sharp fragments is a dangerous practice. If the pressure is strong enough to remove these particles, it will be strong enough to blow them into your eyes, ears or nose, or even the skin. It is far safer to use a brush or vacuum cleaner.  

If you work with compressed air, or if you use it off the job, please remember the following points:  

• Do not play practical jokes with compressed air - it can be fatal.
• Never use compressed air to clean clothing, hair or body.
• Never point the hose at anyone and always see that nearby workers are out of the line of air flow.
• When not actually using the air, point the hose downwards and to the side of the feet.
• If the hose comes apart - and only then - seize at some distance from the business end, block air by bending it, switch off and re-connect.
• Do not leave with air on at the near switch or valve but turn off at the main.
• When crossing passageways, either suspend hose or guard it with boards or runways.
• Use only sound strong hose with secure couplings and connections.
• Wear suitable protective equipment - glasses, face shields, etc.
• Remember normal work clothing is no protection against compressed air.
• Air hoses should be securely held to prevent whipping.

NOTE: Compressed air provided in workplaces contains contaminants which makes it unsuitable for use in air-supplied respiratory protective devices such as spraypainting hoods. Compressed air used with such devices must be appropriately filtered through approved filtration equipment.  

REMEMBER - COMPRESSED AIR IS A KILLER - USE IT SENSIBLY  

The Royal Society for the Prevention of Accidents, London, reports a serious case when employees in a carpenters' shop were using a compressed air hose to remove sawdust from their clothing. One man was seen to push the hose between the legs of a fellow-worker from behind and the man sustained the following injuries:  

• Bruising and bleeding in the area of the rectum;
• Shock;
• Air through tissues over abdomen, chest and neck;
• Hernia canals in the groin ballooned with air;
• Abdomen filled with air;
• Lower bowel torn open in three places, the longest tear being four inches;
• Abdominal cavity filled with bowel material from lower bowel, also contained much fluid and blood; and
• Lining of abdominal cavity torn in several places.

The man was operated upon and blood transfusions given, but he died three days after being injured.

Subsequent investigations revealed that the maximum pressure at the nozzle with the valve turned fully open was about 351 lbs, but the actual pressure at the time of the accident was much less - probably only a third.